Public Policy Matters:
Focus on Driver Distraction and Transportation Law

The DOT Distracted Driving Summit: Highlights and HF/E Challenges
By John D. Lee

     "Sometimes, it takes a lot longer to find a letter on that keyboard than it does to get a cup of coffee." - Comment from a truck driver describing the challenge of driving while typing (Richtel, 2009).

     The issue of driver distraction has recently captured the attention of the media and, as reflected by the Distracted Driving Summit, the attention of policy makers. Convened in Washington, D.C., by U.S. Department of Transportation Secretary Ray LaHood, the summit brought together a highly diverse group to discuss the dangers of driver distraction, potential interventions, and the challenges of implementing those interventions. In response to Secretary LaHood's invitation, 300 attendees were present, and the proceedings, covered by major television networks, were webcast to an audience of more than 5,000.

     This current focus on driver distraction represents a critical opportunity for the human factors/ergonomics community to contribute to solving an important societal problem. Secretary LaHood called the gathering "probably the most important meeting in the history of the Department of Transportation." Whether this event will be seen by the general public as more important than other major transportation initiatives remains to be seen, but it may have lasting implications for those interested in driver distraction.

     HF/E and applied psychology were well represented at the meeting, which also included diverse perspectives from legislators, as well as the editor-in-chief of Seventeen magazine, a panel of teen drivers, and the heads of such major trade associations as CTIA-The Wireless Association and the Consumer Electronics Association. Researchers from the Insurance Institute for Highway Safety and the National Safety Council described the broad literature regarding the challenge of changing driver behavior through information campaigns, noting, for example, that the campaign to promote seat belt use failed, with usage rates increasing only when required by law. Driver distraction may pose a similar challenge. Even though drivers believe that cell phone conversations and texting are distracting, they also admit to talking and texting while driving.

     Speakers repeatedly noted that distraction represents a clear threat to driving safety, accounting for 5,870 deaths in the United States in 2008 (NHTSA, 2009b). Although a great diversity of sources both within and outside the vehicle account for these deaths (e.g., eating, grooming, other motorists, and billboards), the summit focused on technology used in the vehicle -particularly cell phones, Internet connectivity, and texting. Three dimensions of demand have served as a simple way of describing driver distraction: visual (eyes off the road), manual (hands off the wheel), and cognitive (mind off the road). High demands on all three of these dimensions make texting intensely distracting.

     Social pressures on teens and work-related pressures on adults lead to texting while driving. A recent survey showed that teens send an average of 2,899 messages a month, up 566% in the last two years (Covey, 2009). Several tragic crashes provide anecdotal evidence that teens text while driving. A recent naturalistic study of truck drivers showed that texting while driving increased the odds of a crash by approximately 23 times compared with driving without distraction (Hanowski, Olson, Hickman, & Bocanegra, 2009). Several simulator studies confirm this danger (e.g., Drews & Strayer, 2009). In my presentation, I described texting as a sort of perfect storm in which several factors converge to produce a particularly intense distraction: high visual, manual, and cognitive demand combined with an engaging and extended interaction.

     Four senators - Schumer (D-NY), Klobuchar (D-MN), Pryor (D-AK), and Menendez (D-NJ) - spoke in support of a bill that will encourage states to pass laws against texting while driving. Such laws seemed to have broad support from the diverse audience at the meeting, as well as from 90% of the public. Other sources of distraction are more complex and contentious, such as limiting truck drivers' freedom to type messages as they drive (Richtel, 2009).

     There are ample demonstrations of the intensity of distraction associated with texting, some provided by the HF/E community. A more subtle issue that remains to be resolved is the degree to which texting contributed to the 37,261 motor vehicle fatalities in the United States in 2008, relative to the fatalities associated with cell phone conversations and other distractions. Although intense, texting likely comprises shorter and less frequent interactions compared with cell phone conversations. The safety consequences of high-intensity, low-exposure distractions such as texting - relative to those of low-intensity, high-exposure distractions - was a point of substantial discussion at the summit and is an ongoing challenge for the human factors research community.

     Assessing the safety consequences of various distractions represents a central challenge to the HF/E field: How are results from various modes of inquiry harmonized to guide design? In the case of cognitive distraction, a long history of theoretical and empirical findings shows that when people do two things at once, performance on one or both tends to suffer. The degree to which such dual-task performance is governed by various mechanisms, such as the competition between resources or a central bottleneck, is still debated (Levy, Pashler, & Boer, 2006; Wickens, 2002). The data regarding the effect on driving performance, however, are clear. At the summit, William J. Horrey, representing the HFES Surface Transportation Technical Group, clearly summarized several meta-analyses of simulator and on-road studies that show a consistent impairment of drivers attributable to cognitive distraction. Such distraction slows reactions to events by an average of 130-250 ms (Caird, Willness, Steel, & Scialfa, 2008; Horrey & Wickens, 2006). Researchers seem uniform in their agreement that cognitive distraction can impair driver performance.

     Researchers disagree about the magnitude of impairment related to cognitive demands relative to those associated with visual demands and the degree to which cognitive demands undermine driving safety. Summit presenter Thomas A. Dingus concisely articulated one perspective: "In driving, vision is king." The HF/E community faces a challenge in assessing whether or not the relatively mild distraction of cell phone conversation cumulates over a large exposure to produce safety consequences comparable to those of texting.

     The aggregate crash data, epidemiological studies, naturalistic driving studies, and simulator studies conflict. The percentage of drivers using cell phones at any given moment has increased substantially - from 3% in 2001 to 6% in 2005, where it has remained stable (NHTSA, 2009a). However, fatalities and crashes have decreased, suggesting little or no increased risk of cell phone use while driving. At the same time, seat belt use and graduated licensing have increased, which, in the absence of the increased cell phone use, might have substantially reduced fatalities.

     In parallel with the increased use of cell phones and other in-vehicle technology, the United States has also fallen from first in the world in driving safety in 1993 to fourteenth today. Obviously, tracing the effect of cell phone-related distraction to trends in aggregate crash data is challenging.

     Epidemiological studies offer a more precise indicator because they allow one to estimate how the odds of a crash depend on cell phone conversations. Two studies found similar results: an odds ratio of approximately four that did not differ for hands-free or hand-held phones (McEvoy et al., 2005; Redelmeier & Tibshirani, 1997). A study of a completely hands-free device - General Motors' OnStar system - found an odds ratio that did not differ from undistracted driving (Young & Schreiner, 2009). Naturalistic data collected using an instrumentation suite that captures a comprehensive record of driver behavior over months of driving provides an even more precise indicator. Naturalistic data show an odds ratio of 1.3 with a confidence interval that includes 1.0 and, from a recent study of truck drivers, an odds ratio of 0.6 (Klauer, Dingus, Neale, Sudweeks, & Ramsey, 2006). Odds ratios below 1.0 suggest that cell phone conversations provide a protective effect, possibly because they help drivers fight drowsiness.

     It is important to note that the odds ratios from naturalistic studies reflect the combined odds of crashes and near-crash events, because crashes alone are too rare to provide stable estimates. In addition, near-crash events associated with unresponsive drivers, such as those who fail to slow for a red light, are not considered. It is as challenging to generalize near-crash events to crashes as it is to generalize performance decrements in the simulator to diminished driving safety.

     A recent article by Angell (2009) provides a clear explanation for some of these differences and challenges the HF/E community to develop new ways to assess the influence of behavior on safety. She argues that just as the safety devices that improve performance in the simulator - such as early-warning brake lights (Shinar, 2000) - do not always improve safety on the road, distractions that undermine performance may not always diminish safety. At the summit, I presented a complementary perspective based on the idea of spare capacity. Cognitive distraction diminishes drivers' spare capacity, but only in rare situations does this coincide with intense driving demands to lead to a crash. The proliferation of many sources of distraction may also diminish drivers' spare capacity. As a greater proportion of drivers becomes distracted, the spare capacity of the traffic surrounding a distracted driver may also decline, undermining the ability of traffic to compensate for even mild impairments of distracted drivers. Generalizing results from the various modes of inquiry to assess the safety consequences of distraction confronts the HF/E community with a fundamental challenge.

     At the summit, legislators repeatedly requested data to guide decisions, and some argued that naturalistic data are the "gold standard." The complexity of the distraction problems and the limits of any mode of inquiry mean that no simple answer or single method will resolve the problem. The human factors/ergonomics community is far from presenting a harmonized view regarding distraction and driving safety. This challenge was reflected both in the legislators' uncertainty about how broadly to define distraction and in the teen panelists' uncertainty regarding which technologies distract.

     Can HF/E professionals meet the challenges highlighted at the Distracted Driving Summit? We can hope that the ongoing challenge of distraction will help generate techniques that allow us to harmonize the results of controlled laboratory research, observational field studies, and epidemiological approaches.

Resources

Angell, L. (2009). The "looking but not seeing" phenomenon: Could it be happening to us in the practice of our discipline? Surface Transportation Technical Group Newsletter, 16(2), 2-7.

Caird, J., Willness, C., Steel, P., & Scialfa, C. (2008). A meta-analysis of the effects of cell phones on driver performance. Accident Analysis & Prevention, 40, 1282-1293.

Covey, N. (2009, August). Breaking teen myths. Consumer Insight. Retrieved from: http://en-us.nielsen.com/main/insights/consumer_insight/August2009/ breaking_teen_myths

Drews, F., & Strayer, D. (2009). Cellular phones and driver distraction. In M. A. Regan, J. D. Lee, & K. L. Young (Eds.), Driver distraction: Theory, effects, and mitigation. Boca Raton, FL: CRC Press.

Hanowski, R. J., Olson, R. L., Hickman, J. S., & Bocanegra, J. (2009, September). Driver distraction in commercial vehicle operations. Presented at the First International Conference on Driver Distraction and Inattention, Gothenburg, Sweden.

Horrey, W. J., & Wickens, C. D. (2006). Examining the impact of cell phone conversations on driving using meta-analytic techniques. Human Factors, 48, 196-205.

Klauer, S. G., Dingus, T. A., Neale, V. L., Sudweeks, J. D., & Ramsey, D. J. (2006). The impact of driver inattention on near-crash/crash risk: An analysis using the 100-Car Naturalistic Driving Study data (No. DOT HS 810 594). Washington, DC: National Highway Traffic Safety Administration.

Levy, J., Pashler, H. E., & Boer, E. R. (2006). Is there any stopping the psychological refractory period? Psychological Science, 17, 228-234.

McEvoy, S. P., Stevenson, M. R., McCartt, A. T., Woodward, M., Haworth, C., Palamara, P., et al. (2005). Role of mobile phones in motor vehicle crashes resulting in hospital attendance: A case-crossover study. British Medical Journal, 331(7514), 428-430A.

National Highway Traffic Safety Administration (NHTSA). (2009a). Driver electronic device use in 2008 (DOT HS 811 184). Washington, DC: U.S. Department of Transportation.

National Highway Traffic Safety Administration (NHTSA). (2009b). An examination of driver distraction recorded in NHTSA databases. Washington, DC: National Center for Statistics and Analysis, NHTSA.

Redelmeier, D. A., & Tibshirani, R. J. (1997). Association between cellular-telephone calls and motor vehicle collisions. New England Journal of Medicine, 336, 453-458.

Richtel, M. (2009, September 27). Truckers insist on keeping computers in the cab. The New York Times. Retrieved from http://www.nytimes.com

Shinar, D. (2000). Fleet study evaluation of an advance brake warning system. Human Factors, 42, 482-489.

Wickens, C. D. (2002). Multiple resources and performance prediction. Theoretical Issues in Ergonomics Science, 3, 159-177.

Young, R. A., & Schreiner, C. (2009). Real-world personal conversations using a hands-free embedded wireless device while driving: Effect of airbag-deployment crash rates. Risk Analysis, 29, 187-204.

John D. Lee is a professor in the Department of Industrial and Systems Engineering at the University of Wisconsin - Madison. He is also an at-large member of the HFES Executive Council and past chair of the Publications Committee.

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